The Chiefs' Super Rugby road trip struck an unexpected pothole in Perth last night as the resurgent Western Force notched their third successive win for the first time since 2007, stunning the two-time defending champions 18-15 at nib Stadium.

By holding the Chiefs tryless in Australia for the first time since the 2001 Brumbies held their line intact in Canberra, the Force provisionally improve to fifth while the Chiefs had to be content with a bonus point that leaves them third overall and still atop the New Zealand conference.

Six days after clinging on to beat the Highlanders in Dunedin - despite being reduced to 13 men - the Western Australians produced another desperate defensive effort, albeit aided by an error-prone Chiefs outfit that high-tailed it for Johannesburg shortly after fulltime.

The Chiefs finished strongly but knocks-ons by Gareth Anscombe and Tim Nanai-Williams sabotaged any hopes of a match-winning try, summed up a subpar effort that will concern Dave Rennie as he refocuses on the Bulls at Loftus Versfeld on Sunday (NZT).

"It was a really tough game, unfortunately we couldn't get over the line. They deserve the win," said co-captain Aaron Cruden, who lamented the Chiefs shoddy start.

"The attitude wasn't there right from the start. The Force got the bounce on us and it probably flowed right through the game.

"I guess we weren't there mentally."

The Chiefs displayed their trademark doggedness to lead 9-8 at the break after being outplayed in the opening quarter and losing prop Jamie Mackintosh to the sinbin in the 35th minute for persistently impeding the Force's rolling mauls - a key weapon for the home side.

They extended their advantage to 12-8 while a man short - but the Chiefs never really looked comfortable due to a misfiring lineout and the Force's solid scrummage despite the starting pack being outweighed by 41kg.

The Force made an impressive start, dominating possession and territory, while also benefiting from the Chiefs audacious attempt to nudge a 22-metre restart over the line.

Force prop Pek Cowan turned over possession instigating a period of sustained pressure where Sias Ebersohn and Matt Hodgson were thwarted out wide before Mackintosh conceded his first penalty for illegally disrupting a maul.

Hodgson opted to turn down three points and the captain's positivity was rewarded when he peeled off a maul from close range to deservedly opening the scoring.

Cruden nailed a 32-metre penalty to narrow the gap, the first of four penalties that kept the Chiefs in touch, while long range specialist Gareth Anscombe drilled another three-pointer from halfway early in the second spell before the Force regained the ascendancy.

Hodgson, who put in a superb shift in the loose to compensate for the absence of suspended No.8 Ben McCalman, pushed the Force in front in the 45th minute when he powered from another maul - his first double in 103 Super Rugby games.

The Chiefs were fortunate not to concede another try shortly after the restart when a bold counter attack culminated in Nick Cummins putting a foot in touch after being ankle-tapped by Tom Marshall 5m from the line.

However, a crooked lineout throw renewed the pressure and although the Chiefs eventually cleared the danger zone an Ebersohn penalty - after Marshall turned from try-saving hero to a breakdown villain - raised the prospect of the Force avoiding a fourth consecutive loss to their Kiwi nemesis.

Cruden reduced the margin to three heading into the final quarter and although the Chiefs rallied in the dying stages poor handling and resolute defence - personified by prop Kieran Longbottom, who suffered a neck injury when making a desperate tackle on the Force line.

Thankfully he was able to signal 'thumbs up' to an appreciative crowd was he was stretchered off in the 70th minute.

Meanwhile, although the Chiefs lineout maintained its reputation as the least efficient in the competition All Black lock Brodie Retallick was prominent in the tight and loose exchanges.

Flanker Sam Cane also made a solid season debut in the starting line-up and was welcomed back as early as the third minute when former All Black halfback Alby Mathewson rucked the openside at a breakdown - an indiscretion that saw a Force penalty reversed.